The clockspeeds are still unconfirmed, but according to their sources 655MHz will be the final number.
90nm PCIe native 655MHz core frequency 256-bit memory interface 52GB/sec. memory bandwidth 15B pixels/sec. fill rate 1450M vertices/sec. 24 pixels per cycle Built in twin dual-link DVI support for twin 2560x1600 resolution displays
Pictures aren't available yet but the GeForce 7900 GTX will be launched with a dual-slot design. By late March we can expect a single-slot version, designed for Quad SLI setups.
According to other rumours the GeForce 7900 GTX will retail for $499.